Electrically controlled lock



Ap 1968 c. L. ROHMAN 3,377,092

ELECTRICALLY CONTROLLED LOCK Filed April 27, 1967 4 fun-"N702. Cznes/vcs L. RoHMn/v IOTTOENEVJ.

United States Patent 3,377,092 ELECTRICALLY CONTROLLED LOCK Clarence L. Rohman, 5667 Glenfinnan Ave., Azusa, Calif. 91702 Filed Apr. 27, 11967, Ser. No. 634,322 Claims. (Cl. 292-201) ABSTRACT OF THE DISCLOSURE The invention is directed to solenoid-actuated door locks of a projectable bolt type adaptable for sequentially controlling locked and unlocked conditions of a pair of doors leading to a room area to be protected from outside exposure, and aims to provide a locking mechanism that will assure such protection.

Fail-safe performance of the locking mechanism is assured by precluding malfunctioning of either or both the locking bolt or its solenoid actuator by utilizing a gravity projectable bolt and a lost motion spring-interposed connection between the bolt and solenoid core vertically reciprocable above the bolt sothat the spring means transmits bolt projecting movement upon energization of the solenoid and assures downward withdrawal of the core from the solenoid body upon its de-energization. In this manner a combination of such electrically connected locking mechanisms positively assures proper locked and unlocked conditions in the door sequence.

Background of the invention The invention has been occasioned by observations of faulty performance in the operation of lock mechanisms employed in the control of dual door arrangements used in association with so-called clean rooms which require their atmospheres to be kept free from contamination by outside air. In such arrangements both of the doors normally are openable, but upon opening of one door the other becomes locked closed until the opened door closes, thus preventing access of outside open atmosphere communication with the room protected by the dual doors. Should the second door be openable, because of its lock failure in advance of assured closure of the first door, then the room contamination could result.

In the past, lock failures have resulted from malfunctioning of either or both the solenoid actuator or the lock bolt. The present invention aims to preclude such possibilities by must functioning of the bolt and in so mechanically relating it to the actuator as to assure sustained performance of the solenoid.

Summary of the invention The invention contemplates the combination of a solenoid actuator having a vertically reciprocable core responsive to energization of the solenoid, and a bolt which is gravity response to remain normally in retracted or open door position. By use of a spring interposed, lost motion connection between the bolt and solenoid core, upward movement of the latter thrusts the bolt to projected or door locking position, and upon de-energization of the solenoid (as occasioned by closing of a first in progression door) the spring means acts to lower the core and free the bolt for assumption of its retracted position.

More specifically, and in a preferred form, the invention employs a pivoted bolt having its center of gravity so offset from the axis of rotation as to respond normally in retracted position. By the interposition of a balanced coil spring interconnection between the bolt and solenoid core, the spring means accumulates tension in projecting 3,377,092 Patented Apr. 9,1968

the bolt, that is utilized for solenoid is de-energized.

The invention has various features and objects such as the solenoid and bolt mountings for relative vertical adjustment, and employment of a balanced coil spring interconnection, all of which will be more fully understood from the following detailed description of'an illustrative embodiment of the invention shown by the accompanying drawing, in which:

core retraction when the Brief description of the drawings Description of the preferred embodiments The lock structure comprises a mounting base 10 in the form of a plate 11 peripherally thinned at 12 for engagement against a door 13 about a rectangular opening 14 which receives the lock housing 15, plate 11 being secured to the door by screws 16. The door and lock are shown in association with a stationary jamb 17 which may contain any suitable form of keeper, typified by slot 18 within plate 19, for receptoion of the later described bolt;

The lock mechanism is shown to comprise a solenoid 20 mounted within bracket 21' insulated at 22 fro-m the plate 11 and having a lower extension 23 secured to the plate by screws 24. The solenoid is rendered vertically adjustable relative to the bolt and its connections below,

. by accommodating the screw 24 within the bracket slots 25 Although capable of different specific forms, the bolt 26 may take the simple form of a metallic rectangular of uniform thickness secured by key screw 27 to shaft 28. In reference to FIGS. 1 and 2 it will be observed that shaft 28 which is the axis of rotation of the bolt, is offset from the center of the bolt mass so that in the absence of restraint, the bolt assumes by gravity the open or unlocking position of FIG. 1. The bolt is projectable to the locking position of FIG 4 by outward swinging within the mounting plate slot 29. Upon release of the later described spring force, the bolt restores to open position limited by bolt engagement with the bottom edge 30 of the slot 29.

The shaft 28 is journaled for rotation by passage at 31 through openings in spaced parallel flanges 32 of angular brackets 33 secured to the base plate by screws 34. The lock mechanism is characterized by the provision of a spring interposed lost motion connection generally indicated at 35 between the extended core 36 of the solenoid and shaft 28. This lost motion connection comprises in its preferred form a pair of coil springs 37 the upper terminals of which are looped through openings 38 in a cross pieces 39 received within slot 40 in the solenoid core extension and somewhat loosely pivoted therein by a pin or cotter key 41. Some looseness in the cross piece accommodation may be desirable in its tendency to equalize the transmission of spring forces to or from the solenoid core. The lower terminals of the springs 37 are connected to shaft 28 by reception within the loops of cotter pins 42 inserted through openings in the shaft beyond the supports 32.

The described mechanism is shown to be enclosed within housing 15 detachably secured to the base plate 11 by screws 43. Lead conductors 44 are shown in FIG. 2

to extend from the solenoid outwardly through the housing to a suitable multiple door control of knowntype and with which the present invention is not concerned. As known to those familiar with clean room door controls, multiple electrically energizable door locks are governed by such controlls so that in the sequence of passage through a pair of normally unlocked closed doors, the one first opened will cause the second door to lock until the first door closes, whereupon both doors restore to unlocked condition.

In considering the operation of the present lock, assume first the parts to be positioned in FIG. 1 with the bolt 26 retracted to allow opening of the door. Upon door closure a remote control energizes the solenoid 20 elevate its core 36 and in so doing to transmit through the springs 37 yielding force which swings the bolt to its door locking position of FIG. 4. Thereafter, upon de-energization of the solenoid, its core drops both by gravity and the pull of springs 37 to restore the parts as is FIG. 1. The force transmission through the springs has an important advantage in assurance against binding of the core 36 within the solenoid during any continued current feed to the solenoid that otherwise might cause its impairment. By reason of its off center unbalance mounting, the bolt is assured of gravity restoration to open position upon release or lessening of the spring tension as the solenoid opens.

I claim: 1. Locking mechanism comprising a supporting base mountable on a door or the like, an electrically energizable solenoid including a body carried by said base and containing a vertically reciprocable core, a bolt carried by the base below the solenoid and movable from a normal retracted open position to a projected locking position, and a lost motion connection between said core and bolt including spring means by which upward movement of the core upon energization of the solenoid moves the bolt from retracted too projected position, said spring means acting to lower the core upon de-energization of the solenoid.

2. Locking mechanism according to claim 1, including means mounting said solenoid for vertical adjustment relative to the bolt.

according to claim 1, in which gravity from propected to re- 3. Locking mechanism said bolt is movable by tracted position.

4. Locking mechanism according to claim 2, in which said bolt is pivoted to swing between said positions and has its center of gravity oflfset from the pivot axis.

5. Locking mechanism according to claim 4, including a shaft fixed to the bolt for pivoting thereof, and bracket means at opposite sides of the bolt mounting the shaft to said base.

6. Locking mechanism according to claim 5, in which said spring means is attached to said shaft.

7. Locking mechanism according to claim 6, in which said spring means comprises a pair of coil springs at opposite sides of said bracket means.

8. Locking mechanism according to claim 7, including a cross T-arm movably carried by said core and to which said springs are connected.

9. Locking mechanism according to claim 8, including cotter keys connecting the springs to said shaft and a cotter key centrally connecting said T-arm to the core.

10. Locking mechanism according to claim 8, in which said base is a plate containing an aperture through which the bolt extends, and comprising means mounting said solenoid for vertical adjustment on said plate.

References Cited UNITED STATES PATENTS 2,219,132 10/1940 Hohmann et a1. 292-201 X 1,319,187 10/19'19 Summers 292-238 2,325,225 7/1943 Burke 292-201 X 2,647,789 8/1953 Chayne 292144 X FOREIGN PATENTS 293,675 8/1916 Germany.

1,184 12/ 1911 Great Britain.

RICHARD E. MOORE, Primary Examiner. 

